A spurline filter is an effective band rejection filter. With reference to prior art FIG. 1, a layout of a prior art single-resonator spurline filter 100 includes a through-line 101 of the filter and a single spur 102. The single-resonator spurline filter 100 provides a band rejection notch at a resonant frequency of an incident signal. Similarly, FIG. 2 illustrates a dual-resonator spurline filter 200 comprising a through-line 201 of the filter, a first spur 202, and a second spur 203. In general, a dual-resonator spurline filter provides a wider band frequency rejection response than the single-resonator spurline filter.
In both single and dual spurlines, the length of the spur is designed to be a quarter wavelength (¼ λ) in length, and thus determines the band rejection center frequency. Therefore, a spurline filter can be designed with a different center frequency of the band rejection by adjusting the spur length. However, a spurline filter configured to be an effective band rejection filter generally results in a large filter size, particularly in length. Thus, a need exists for improved spurline filter systems, methods and devices for addressing these and other issues.